66641688 has 24 divisors (see below), whose sum is σ = 180488100. Its totient is φ = 22213872.

The previous prime is 66641677. The next prime is 66641711. The reversal of 66641688 is 88614666.

It is a tau number, because it is divible by the number of its divisors (24).

It is a super-2 number, since 2×66641688² = 8882229158978688, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 462718 + ... + 462861.

Almost surely, 2^66641688 is an apocalyptic number.

It is an amenable number.

66641688 is an abundant number, since it is smaller than the sum of its proper divisors (113846412).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66641688 is a wasteful number, since it uses less digits than its factorization.

66641688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 925591 (or 925584 counting only the distinct ones).

The product of its digits is 331776, while the sum is 45.

The square root of 66641688 is about 8163.4360412758. The cubic root of 66641688 is about 405.4294849467.

It can be divided in two parts, 6 and 6641688, that multiplied together give a triangular number (39850128 = T₈₉₂₇).

The spelling of 66641688 in words is "sixty-six million, six hundred forty-one thousand, six hundred eighty-eight".